WASHINGTON — First lady Michelle Obama launched a nationwide campaign Tuesday to fight childhood obesity, part of her effort to teach America's children about better nutrition and exercise.

Mrs. Obama said the Let's Move campaign will encourage more physical activity for children, healthier food in schools and more accurate food labeling. Some of her initiatives, such as tax breaks for grocery stores to move into poorly served communities, will require congressional action.

"I would move heaven and earth to give my kids all the chance in the world for them to be at the top of their game in every way, shape and form," Mrs. Obama told USA Today. "Let's Move operates under the principle that every family wants the same thing for their kid. So we're going to figure out how to make it easier for them to get it."

In the Oval Office on Tuesday, President Barack Obama signed a memorandum creating a task force on childhood obesity. Its members, including the secretaries of health, agriculture, education and the interior, must report back within 90 days.

He praised his wife, who attended the signing, for tackling one of "the most urgent health issues facing the country."

"This has enormous promise in improving the health of our children, in giving support to parents to make the kinds of healthy choices that are often very difficult," Obama said.

In an interview with ABC News, Mrs. Obama acknowledged
her love of burgers and fries
, and ice cream and cake, as do most kids. But she said she wants her daughters and the rest of the nation's children to practice better nutrition and exercise, too.

"We're not talking about a lifestyle that excludes all that," she said. "The question is how do we help people balance that out so that they're not facing life-threatening, preventable illnesses, but they're enjoying their food, they're eating their vegetables, they're doing their running and walking and playing and still have time to get a good, fun meal in every once in a while."

"There's no expert on this planet that says the government telling people what to do really does any good on this issue," Mrs. Obama said. "This is going to require an effort on everyone's part. We have to have a tailored approach on this."

She planned an elaborate announcement Tuesday at the White House. Scheduled to join her in the State Dining Room were Cabinet members, mayors, doctors, media, sports, entertainment and business leaders.

In the ABC interview, Mrs. Obama said she tries every day to instill the same values in her daughters, Malia, 11, and Sasha, 8.

"My kids have to get up and move. They can't sit in front of the TV," she said. "I have them involved in sports ... to compete and to win and to run and to sweat. They have to understand."

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